Glazing panel systems have found a wide variety of uses in the design of various architectural structures as they are a strong, lightweight alternative to the traditional material, glass, which they often replace. For instance, modular glazing panels can be used with a framing grid of purlins and rafters to form overhead or roofing structures such as for covered walkways, pool enclosures, building atriums, greenhouses, etc. Glazing panels generally have light transmissive properties so that their use is particularly preferred where it is desired to allow sunlight to pass through the structure such as to illuminate interior regions of a building. An additional advantage promoting the use of glazing panel systems is the energy conservation they afford.
Glazing panel systems used for roof and wall constructions must be capable of resisting both the static and dynamic loads as well as the impact loads to which they will be subjected, carrying them satisfactorily to the walls and/or other supporting structures and providing protection from the elements. Principle roof loads are created by high winds, and in the northern climates, by snow and ice. The evaluation of pressures exerted by wind on a building is complex, and local code requirements for wind forces can vary widely depending on the weather extremes expected in the area. The recommended design wind pressure on plane surfaces which are normal to the wind increases with the height of the structure above ground level. Wind on the windward roof slope may produce suction or pressure depending on the slope of the roof. Leeward slopes are generally always subject to the effects of suction.
Hurricanes bring high, swirling winds against building structures and can cause damage by penetrating building envelopes such as by breaking windows due to flying debris or high wind pressure allowing wind to rush into the building pressuring the interior thereof. The vacuum caused by high winds rushing over the roof in conjunction with the pressurized interior of the building can cause the roof to be pulled off from its supporting structure. In extreme weather regions, such as in the hurricane ravaged areas of Florida, rigorous testing standards are being employed in new building codes to address the structural damage caused by hurricanes due to inadequate building construction. For example, testing in Dade County subjects windows and skylights to pressure testing of 4500 inward and outward wind pressure cycles to simulate a hurricane wind flow against a building as the eye of the storm passes. Thus, the challenge for glazing panel manufacturers is to design products that meet the new rigorous codes. One such standard adopted in most of the Southeast is that established by the American Society of Civil Engineers, ASCE-7, which can dictate design pressures of more than 100 psf (pounds per square foot) for high coastal buildings.
In a particular glazing panel system of interest herein, the glazing panels are provided with upstanding seam flanges which extend along their side edges for being connected with adjacent panels with batten-type joining connectors. The seam flanges are provided with projecting saw teeth and the battens have internal saw teeth so that when the batten is pushed over abutting seam flanges of adjacent panels, the saw teeth of each cooperate to snap-fit the saw teeth together joining the adjacent panels.
Retention clips are used to keep joined panels anchored to the roof framework or supporting structure therebelow. Accordingly, the integrity of the roofing panel system relies on the clip to keep the roof secured in place during high wind load conditions. The clips that are currently used in the above-described panel system are very small and are die stamped from sheet metal, such as stainless steel and have a thickness of approximately 0.8 mm. The clips are placed between the seam flanges which are then joined by the batten snap fit thereover. A small base of the clip can then be fastened to the purlin or rafter of the supporting structure. The clips are small enough so that they are hidden from view by the supporting framework and between the seam flanges. However, the current small, stamped clips are not particularly well-suited for the high wind loads such as seen in Dade County and other hurricane regions. Accordingly, there is a need for a high performance glazing panel system and a retention clip therefor that are effective to keep the panel system anchored in place when subjected to high loads, such as due to the forces generated by high winds during hurricanes.